Fiddler offers many ways to gather traffic from mobile devices; in most cases, you simply turn off the device’s cellular connection, enable WiFi, and point the device’s proxy settings at your desktop PC running Fiddler.

Fiddler’s AutoResponder makes it easy to test how your site behaves when any of its constituent resources are slow or unavailable. With the AutoResponder, you can selectively choose resources to delay or fail, and ensure that your client-side experience recovers as best it can.